Exam 4 - Chapter 9 Flashcards
1
Q
skeletal muscle characteristics
A
attached to bone, striated, voluntary
2
Q
what does it mean for muscles to be voluntary
A
consciously decide to contract
3
Q
smooth muscle characteristics
A
involuntary, non-striated
4
Q
cardiac muscle characteristics
A
in the heart, striated, irregular branching pattern, linked by intercalated discs
5
Q
what does it mean for muscle tissue to be excitable
A
respond to stimuli by generating voltage channels
6
Q
what stimuli do muscle tissue respond to
A
chemicals, physical forces, charge changes
7
Q
what does it mean for muscle tissue to be conductive
A
local charge change triggers wave of change through action potential traveling down the cell
8
Q
what does it mean for muscle tissue to be extensible
A
muscle fibers can stretch
9
Q
what does it mean for muscle tissue to be contractible
A
muscle fibers can shorten
10
Q
what does it mean for muscle tissue to be elastic
A
muscle fibers recoil to original length after stretching
11
Q
skeletal muscle anatomy
A
composed of fascicles of muscle tissue that are surrounded by epimysium
12
Q
fascicle
A
bund of muscle fibers
13
Q
fascicles are surrounded by
A
perimysium
14
Q
muscle fiber
A
single muscle cell
15
Q
muscle cell characteristics
A
very long cell filled with myofibrils and multiple nuclei that are pushed to the periphery
16
Q
myofibril
A
bundle of actin and myosin protein myofilaments
17
Q
muscle striation is caused by
A
overlapping myofilaments of actin and myosin
18
Q
sarcomere
A
segment of myofibril that is the functional, contractile unit of a muscle fiber
19
Q
structure hierarchy of skeletal muscle
A
muscle, fascicle, fiber, sarcomere, myofilament
20
Q
endomysium surrounds ____
perimysium surrounds ____
epimysium surrounds ____
A
endomysium surrounds muscle fibers
perimysium surrounds muscle fascicles
epimysium surrounds the entire muscle
21
Q
tendons attach
A
muscle to bone
22
Q
tendon is made of
A
dense regular connective tissue
23
Q
sarcolemma
A
plasma membrane of muscle fiber
24
Q
sarcoplasm
A
cytoplasm of muscle fiber
25
glycogen
carbohydrate and energy storage in the fiber
26
myoglobin
red pigment that provides oxygen in muscle fibers
27
sarcoplasmic reticulum
smooth er of the muscle fiber that acts as a calcium reservoir
28
parts of the sarcoplasmic reticulum
terminal cistern, t-tubule, triad
29
terminal cistern
dilated end of SR
30
t-tubule
transverse tubules of the plasma membrane that penetrate across the cell
31
triad
t-tubule and two terminal clusters
32
myofilaments create
movement that causes contraction
33
myofilaments can be ___ or ___
thick or thin filaments
34
thick filament is made of
myosin
35
myosin
two golf-club like chains with global heads
36
thin filament is made of
actin, tropomyosin, and troponin
37
tropomyosin
protein that blocks actin active sites
38
troponin
three protein complex atop tropomyosin that binds to calcium
39
striation
visible bonding due to organization of thick and thin filaments
40
striation is seen in what types of muscles
cardiac and skeletal
41
striation is alternating bands of
dark A and light I bands
42
sarcomere is a functional unit segment from
z-disc to z-disc
43
z-disc
anchor point for thin and elastic filaments
44
a-band
dark band of thick filaments and overlapping thick/thin filaments
45
h-band
center region of the a-band that is made of thick filaments
46
m-line
middle of h-band
47
i-band
light band of thin filaments, elastic filaments, and z-discs
48
elastic filaments
made of a titin protein that runs through the center of thick filaments
49
function of elastic filaments
anchor myofilaments to z-discs and m-line, prevent overstretching, and provide recoil
50
dystrophin
links outer myofilaments to the endomysium of the muscle fiber
51
dystrophin function
transfers the force of contraction to connective tissue and tendons
52
muscular dystrophy is a defect of
dystrophin
53
muscle contraction is due to
sarcomere shortening
54
contraction occurs when
thick filaments pull thin filaments toward the center
55
what happens to myofilaments in contraction
don't shorten, but increase in the overlap of filaments
56
what happens to z-discs in contraction
z-discs move closer as thin filaments move
57
contraction is triggered when the _____ _____ releases _____ into the sarcoplasm
Sarcoplasmic Reticulum, Calcium
58
skeletal muscles only contract when stimulated by
a nerve
59
somatic muscle fibers
axons of nerves that supply muscle fibers
60
a muscle fiber is supplied by ___ nerve fiber, a nerve fiber can supply ___ muscles
muscle fiber is supplied by one nerve fiber
nerve fiber can supply many muscles
61
somatic muscle fiber location
branch throughout the muscle organ to ensure contraction of the entire organ
62
motor fibers contract by themselves/ in unison
in unison
63
muscle fibers require one/multiple units to contract
multiple units
64
units contract all at once/take turns
take turns to avoid fatigue
65
small motor units
3-6 muscle fibers per neuron that control fine motor of hands and eyes
66
large motor units
up to 1000 muscle fibers per neuron that are used for movements of great strength and less control
67
muscle contain either or / both types of motor units
both types
68
size principle
the larger the motor unit, the less sensitive the muscle is to stimulation
69
neuromuscular junction
where somatic motor fiber reaches the muscle fiber
70
motor end plate
sarcolemma at NMJ
71
axon terminal
swollen end of the nerve fiber that releases ACh
72
ACh receptors
receptor proteins found on the sarcolemma
73
ACh receptors are found in
the junctional fold
74
junctional fold
indentations that increase sarcolemma surface area
75
synaptic cleft
gap between the axon terminal and sarcolemma that contains AChE
76
muscle action potentials are excitable, meaning
stimulation changes voltage across the membrane
77
RMP of muscle fibers is
90 mV
78
Phases of Muscle Behavior
excitation, excitation-contraction coupling, contraction, relaxation
79
excitation
the process by which action potentials in the nerve lead to action potentials in the muscle
80
excitation in the neuron
1) action potential arrives at the axon terminal
2) voltage-gated calcium channel opens
3) calcium enters the axon terminal and synaptic vesicles release ACh
81
excitation in the synaptic cleft
1) ACh travels through the synaptic cleft
2) ACh binds to the receptors on the Sarcolemma
82
excitation in the muscle fiber
1) end plate potential generated
2) action potential is generated
83
how is the end plate potential generated
ACh receptor sodium/potassium ion channels open, sodium flows in, and voltage depolarize the motor end plate from RMP to 60 mV
84
muscle fiber depolarization
sodium flows into the sarcolemma and voltage goes from -90 mV to slightly positive
85
muscle fiber repolarization
potassium flows out of the sarcolemma and potential returns to 90 mV
86
excitation-contraction coupling
link between the action potentials of the sarcolemma and the activation of myofilaments
87
excitation-contraction coupling steps
1) action potential enters t-tubules
2) calcium channels in the terminal cisternae open
3) calcium binds to troponin on thin filaments
4) active sites on actin of thin filaments are exposed
88
where does the calcium go when channels open in the terminal cisternae during the excitation-contraction coupling
calcium diffuses out of the sarcoplasmic reticulum into the cytosol
89
terminal cisternae
dilated end of the SR associated with t-tubules
90
how are the active sites of actin on thin filaments exposed?
calcium-binding changes the troponin-tropomyosin complex shapes and shifts to allow access to the active sites
91
contraction
muscle fibers develop tension and usually shorten
92
muscle tension/tone
force generated in a cell to cause a contraction or resist extension
93
contraction is best explained by the
sliding filament theory
94
contraction is linear/circular
a cycle
95
cycle of contraction
recovery stroke, actin-myosin cross-bridge formation, myosin power stroke, actin released by myosin
96
recovery stroke of contraction
myosin head extends into a high-energy position
97
how does the myosin head extend in the recovery stroke
ATP is hydrolyzed to ADP+P , and the energy released cocks the head
98
actin-myosin cross-bridge forms when
myosin head binds to actin active site
99
myosin power stroke action
ADP+P unbinds from the myosin, causing the myosin to return to a lower energy position
100
the myosin power stroke causes the actin filament to
be dragged along and the muscle fiber to shorten
101
what happens when myosin releases actin during contraction
ATP rebinds to myosin and the process is repeated
102
relaxation in contraction
muscles lose tension and return to its resting length
103
steps of relaxation
1) nerve signals stop
2) ACh is broken down
3) SR reabsorbs Calcium
4) Calcium lost from troponin
5)Tropomyosin blocks actin active sites
6) Muscle Returns to resting length
104
what happens in muscle relaxation to break down ACh
ACh dissociates from Ach receptors, AChE breaks down ACh
105
what happens when calcium is lost from troponin
calcium dissociates and is reabsorbs SR
106
What causes tropomyosin to block actin sites
calcium dissociates from troponin
107
muscle returns to resting length due to
action of an antagonist muscle or an outside force (gravity)
108
what steps of relaxation are constant in all other phases of contraction
SR reabsorption of calcium and calcium loss from troponin
109
the length-tension relationship
amount of tension generated on how stretched/shortened the muscle was before contraction
110
what happens when a muscle is too short
weak tension because thick filaments bump z-discs
111
what happens when a muscle is too long
weak tension because there is little actin-myosin overlap and few cross bridges
112
what maintains muscle tension
nervous system maintain tension near optimal length
113
muscle twitch
single cycle of muscle fiber contraction/relaxation
114
myogram
chart tracking timing and strength of muscle organ twitch
115
phases of muscle twitches
latent Period, contraction phrase, relaxation phase
116
latent period
brief delay between stimulus and contraction
117
the latent period contains what stages of contraction
excitation and excitation-contraction coupling
118
contraction phase
when muscle generates tension
119
contraction phase includes what phases of contraction
sliding-filament steps
120
relaxation phase
tension returns to resting levels
121
relaxation phase corresponds to what phases of contraction
throughout contraction and relaxation
122
a single twitch generates how much tension
little
123
wave summation
addition of multiple twitches to generate more tension
124
wave summation is also called
temporal summation
125
how is more tension generated
second twitch starts before the first ends
126
tetanus
sustained muscle contraction through wave summation
127
incomplete/unfused tetanus
sustained muscle fiber contraction where the fiber relaxes slightly before the next
128
complete/fused tetanus
sustained muscle fiber contraction with no relaxation
129
complete tetanus can only occur with
rapid stimulation
130
isometric contraction
same length contraction where muscle produces internal tension but doesn't shorten
131
purpose of isometric contraction
maintaining posture, stabilizing joint, prelude to movement
132
isotonic contraction
same tension contraction where muscle changes length without changing in tension
133
concentric contraction
muscle shortens as it maintains tension
134
eccentric contraction
muscle lengthens as it maintains tension
135
isometric contraction has the same _____ of contraction, isotonic contraction has the same ____ of contraction
length, tension
136
muscles need ___ to contract
ATP
137
anaerobic fermentation
requires no oxygen and produces lactate and little atp
138
aerobic respiration
requires continuous oxygen and produces lots of ATP but not lactate
139
which type of metabolism requires oxygen
aerobic respiration
140
which type of metabolism produces lactate
anaerobic fermentation
141
stages of ATP synthesis during exercise
1) immediate aerobic respiration
2) phosphagen system
3) glycogen-lactate system
4) long term aerobic respiration
5) Excess Postexercise Oxygen Consumption
142
immediate aerobic respiration
oxygen supplied by myoglobin is quickly depleted
143
immediate aerobic respiration uses what source
atp stored in muscle fiber
144
immediate aerobic respiration lasts
5 seconds
145
in aerobic respiration, how much atp is produced per glucose
30 ATP
146
phosphagen system
ATP is made by transferring phosphates from other molecules to ADP
147
what two enzymes does the phosphagen system use
myokinase and creatin kinase
148
myokinase
enzyme that transfers phosphate from one ADP to another
149
creatine kinase
takes phosphate from creatine phosphate and gives it to ADP
150
glycogen-lactate systems is
anerobic fermentation
151
phosphagen system lasts how long
10 seconds
152
in the glycogen-lactate system glycolysis converts glucose to
2 ATP and pyruvic acid
153
glycogen lactate system lasts
40 seconds
154
long term aerobic respiration
when the respiratory and cardiovascular systems catch up and can deliver more oxygen
155
how long does long term aerobic respiration last
30 minutes
156
what causes long term aerobic respiration to end
glycogen stored in the muscles are exhausted and fatty acids must become the source of fuel
157
what does EPOC stand form
Excess Postexercise Oxygen Consumption
158
EPOC begins
immediately after ending exercise
159
EPOC is needed to
aerobically replenish ATP, restore oxygen to myoglobin, liver, cells with higher metabolic rates, and restore creatin phosphate levels
160
Type I muscle fiber
slow-twitch
161
Type I muscle fibers are what color
red
162
slow twitch fiber characteristics
high endurance and fatigue resistant
163
slow twitch muscle fibers use what type of metabolism
aerobic respiration
164
slow twitch muscle fibers are more prevalent in which type of muscle
muscles that maintain posture
165
type II muscle fibers are
fast twitch
166
type II muscle fibers are what color
white
167
fast twitch muscle fibers characteristics
low endurance, fast and powerful response
168
fast twitch muscle fibers use what type of muscle metabolism
anaerobic respiration
169
fast twitch muscle fibers are more prevalent in what types of muscles
quick and powerful muscles
170
type IIA muscle fibers
intermediate fibers
171
type IIA characteristics
fast twitch and fatigue resistance
